Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual foi o número total de anos em que o melhor cantor (躍進歌手) mais melhorou?
 ###Tabelas: CREATE TABLE electoral_results (electoral_results_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Candidates nominated INT, Candidates elected VARCHAR, Votes INT, % of national vote INT) CREATE TABLE awards_and_nominations (awards_and_nominations_id AUTO_INCREMENT PRIMARY KEY, Year INT, Award VARCHAR, Category VARCHAR, Nomination VARCHAR, Result VARCHAR) CREATE TABLE results_of_the_national_championships_-_1980_to_1995 (results_of_the_national_championships_-_1980_to_1995_id AUTO_INCREMENT PRIMARY KEY, Year INT, Venue VARCHAR, Men's Open VARCHAR, Women's Open VARCHAR, Men's 35s VARCHAR) CREATE TABLE monthly_mobile_subscriber_additions (monthly_mobile_subscriber_additions_id AUTO_INCREMENT PRIMARY KEY, Year INT, January INT, February INT, March INT, April INT, June INT, July INT, August INT, September INT, October INT, November INT, December INT, Annual Additions(in millions) INT, Average Monthly Additions(in millions) INT) CREATE TABLE 1965 (1965_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, City VARCHAR, Opponent VARCHAR, Results¹ VARCHAR, Type of game VARCHAR)  
SELECT SUM Year FROM awards_and_nominations WHERE Category = best improved singer (躍進歌手)